Platen support, 2x42

E

ernestrome

Joined
Jan 25, 2006
Messages
211
Hi,

I use a 2x42 grinder, the older 3 wheel model. The platen is a piece of bent 1/8 steel, approx 5-6" in height. I would like to make a longer platen so i can more easily put a longitudinal brushed finish on my knives (before finishing them by handrubbing). I plan to make a longer one by bending or welding so i have a 2 inch by 10" platen, and a 2x3" tab at the bottom by which it is mounted onto the grinder body. Alternatively I could get a heavy corner brace or piece of heavy angle 2" wide and bolt the platen to it.

The problem is I need to prevent the top of the platen being pushed back from the belt by the pressure of grinding. This already happens to some degree with the current platen, it will be at least twice as bad with the longer platen. The top tracking wheel also moves in an arc to provide tension, so there must be some control over the the position of the top point. The bottom point is varied using a bolt and slot.

I would like to use one or two bolts or pushers to provide support for the top edge of the platen.
I could glue a piece of wood or metal to the body just below the contact wheel so that bolts could be fed through and push on the top backside of the platen.
Or I could those things that have two threaded parts and a tube, such that when the tube is turned both bolts either extend or retract but I am not sure what they are called. Can anyone help me with the name? It is the kind of the opposite of a threaded tensioner for wire. Ideally they have free turning ball and socket plates so i can glue the plates onto the rear of the platen and the grinder body and then twist the tube to vary the amount the top of the platen is pushed out towards the belt.

Does anyone have any thoughts or suggestions?
 
I just found the model you are talking about yesterday on craigslist and picked it up. I was wondering the same thing. I haven't looked closely at it yet so tonight hopefully i will get a chance to take a peek. I bought a 2x6 ceramic platten from HighTempTools with the intent of using it on the newer model so I'm going to try to make it work on this one. You seem to be looking at something bigger, so I'd be interested in what anyone else has done with this "older" model.
 
I have made a few mods to mine. A 1.5hp 1725 motor to slow it down. A rubber inner tube covered drive wheel to prevent belt slip. A cork faced contact / tracking wheel.

I have experimented with graphite tape for the platen too.


I would love to add a receiving tube for a kmg style tool arm, then I could use longer belts, contact wheels etc.

If you put the glass on the current platen I recommend you use something to support the top edge Si that the bending i described doesn't crack it. You could simply use a wooden brace with a wedge. Also use a small lip so if the glass gets loose it doesn't fall into the bottom wheel and you end up with a face full of shards.
 
Great ideas all. I have a 1hp motor with VFD that I was planning on using with the current, 1/3hp version. It seems kinda silly to use it since this unit already has a 1hp motor but I think the VFD will be very nice.

I too was thinking about adding a tool arm receiver to i could add another wheel off the back of the machine to use 2x72" belts, though I'm not sure if my 1hp would be able to handle it.

For the platen I was thinking of simply welding 2 triangular braces to the back of it, then attaching the ceramic platen with something physically below it to prevent it dropping (two short bolts or something similar).
 
Haha, more like half horsepower, plus it is open. Works OK for the disk but you will regret not putting the vfd and real motor on sooner if you delay!

My plan was to extend forward not back. If you have the two wheel version you could go backward, but with the three wheel i would expose the lower wheel by cutting the body and run the belt out to a new platen on the tool arm. You need to maintain a large wrap on the drive wheel to prevent slip.o it could move the drive wheel back but you must cut away much more of the body that way.

https://sites.google.com/site/alexnharvey/home/knifemaking/craftsman-2x42-grinder
 
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